Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 377 insertions, 0 deletions

diff --git a/layout/mathml/nsMathMLmfracFrame.cpp b/layout/mathml/nsMathMLmfracFrame.cpp
new file mode 100644
index 0000000000..fc43d2dff1
--- /dev/null
+++ b/layout/mathml/nsMathMLmfracFrame.cpp
@@ -0,0 +1,377 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMathMLmfracFrame.h"
+
+#include "gfxUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPrefs_mathml.h"
+#include "nsLayoutUtils.h"
+#include "nsPresContext.h"
+#include "nsDisplayList.h"
+#include "gfxContext.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/MathMLElement.h"
+#include <algorithm>
+#include "gfxMathTable.h"
+#include "gfxTextRun.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+//
+// <mfrac> -- form a fraction from two subexpressions - implementation
+//
+
+nsIFrame* NS_NewMathMLmfracFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsMathMLmfracFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmfracFrame)
+
+nsMathMLmfracFrame::~nsMathMLmfracFrame() = default;
+
+eMathMLFrameType nsMathMLmfracFrame::GetMathMLFrameType() {
+  // frac is "inner" in TeXBook, Appendix G, rule 15e. See also page 170.
+  return eMathMLFrameType_Inner;
+}
+
+uint8_t nsMathMLmfracFrame::ScriptIncrement(nsIFrame* aFrame) {
+  if (StyleFont()->mMathStyle == StyleMathStyle::Compact && aFrame &&
+      (mFrames.FirstChild() == aFrame || mFrames.LastChild() == aFrame)) {
+    return 1;
+  }
+  return 0;
+}
+
+NS_IMETHODIMP
+nsMathMLmfracFrame::TransmitAutomaticData() {
+  // The TeXbook (Ch 17. p.141) says the numerator inherits the compression
+  //  while the denominator is compressed
+  UpdatePresentationDataFromChildAt(1, 1, NS_MATHML_COMPRESSED,
+                                    NS_MATHML_COMPRESSED);
+
+  // If displaystyle is false, then scriptlevel is incremented, so notify the
+  // children of this.
+  if (StyleFont()->mMathStyle == StyleMathStyle::Compact) {
+    PropagateFrameFlagFor(mFrames.FirstChild(),
+                          NS_FRAME_MATHML_SCRIPT_DESCENDANT);
+    PropagateFrameFlagFor(mFrames.LastChild(),
+                          NS_FRAME_MATHML_SCRIPT_DESCENDANT);
+  }
+
+  // if our numerator is an embellished operator, let its state bubble to us
+  GetEmbellishDataFrom(mFrames.FirstChild(), mEmbellishData);
+  if (NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags)) {
+    // even when embellished, we need to record that <mfrac> won't fire
+    // Stretch() on its embellished child
+    mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
+  }
+
+  return NS_OK;
+}
+
+nscoord nsMathMLmfracFrame::CalcLineThickness(nsPresContext* aPresContext,
+                                              ComputedStyle* aComputedStyle,
+                                              nsString& aThicknessAttribute,
+                                              nscoord onePixel,
+                                              nscoord aDefaultRuleThickness,
+                                              float aFontSizeInflation) {
+  nscoord defaultThickness = aDefaultRuleThickness;
+  nscoord lineThickness = aDefaultRuleThickness;
+  nscoord minimumThickness = onePixel;
+
+  // linethickness
+  // https://w3c.github.io/mathml-core/#dfn-linethickness
+  if (!aThicknessAttribute.IsEmpty()) {
+    lineThickness = defaultThickness;
+    ParseNumericValue(aThicknessAttribute, &lineThickness,
+                      dom::MathMLElement::PARSE_ALLOW_NEGATIVE, aPresContext,
+                      aComputedStyle, aFontSizeInflation);
+    // MathML Core says a negative value is interpreted as 0.
+    if (lineThickness < 0) {
+      lineThickness = 0;
+    }
+  }
+  // use minimum if the lineThickness is a non-zero value less than minimun
+  if (lineThickness && lineThickness < minimumThickness)
+    lineThickness = minimumThickness;
+
+  return lineThickness;
+}
+
+void nsMathMLmfracFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                                          const nsDisplayListSet& aLists) {
+  /////////////
+  // paint the numerator and denominator
+  nsMathMLContainerFrame::BuildDisplayList(aBuilder, aLists);
+
+  /////////////
+  // paint the fraction line
+  DisplayBar(aBuilder, this, mLineRect, aLists);
+}
+
+nsresult nsMathMLmfracFrame::AttributeChanged(int32_t aNameSpaceID,
+                                              nsAtom* aAttribute,
+                                              int32_t aModType) {
+  if (nsGkAtoms::linethickness_ == aAttribute) {
+    InvalidateFrame();
+  }
+  return nsMathMLContainerFrame::AttributeChanged(aNameSpaceID, aAttribute,
+                                                  aModType);
+}
+
+/* virtual */
+nsresult nsMathMLmfracFrame::MeasureForWidth(DrawTarget* aDrawTarget,
+                                             ReflowOutput& aDesiredSize) {
+  return PlaceInternal(aDrawTarget, false, aDesiredSize, true);
+}
+
+nscoord nsMathMLmfracFrame::FixInterFrameSpacing(ReflowOutput& aDesiredSize) {
+  nscoord gap = nsMathMLContainerFrame::FixInterFrameSpacing(aDesiredSize);
+  if (!gap) return 0;
+
+  mLineRect.MoveBy(gap, 0);
+  return gap;
+}
+
+/* virtual */
+nsresult nsMathMLmfracFrame::Place(DrawTarget* aDrawTarget, bool aPlaceOrigin,
+                                   ReflowOutput& aDesiredSize) {
+  return PlaceInternal(aDrawTarget, aPlaceOrigin, aDesiredSize, false);
+}
+
+nsresult nsMathMLmfracFrame::PlaceInternal(DrawTarget* aDrawTarget,
+                                           bool aPlaceOrigin,
+                                           ReflowOutput& aDesiredSize,
+                                           bool aWidthOnly) {
+  ////////////////////////////////////
+  // Get the children's desired sizes
+  nsBoundingMetrics bmNum, bmDen;
+  ReflowOutput sizeNum(aDesiredSize.GetWritingMode());
+  ReflowOutput sizeDen(aDesiredSize.GetWritingMode());
+  nsIFrame* frameDen = nullptr;
+  nsIFrame* frameNum = mFrames.FirstChild();
+  if (frameNum) frameDen = frameNum->GetNextSibling();
+  if (!frameNum || !frameDen || frameDen->GetNextSibling()) {
+    // report an error, encourage people to get their markups in order
+    if (aPlaceOrigin) {
+      ReportChildCountError();
+    }
+    return PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize);
+  }
+  GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum);
+  GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen);
+
+  nsPresContext* presContext = PresContext();
+  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
+
+  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
+  RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
+
+  nscoord defaultRuleThickness, axisHeight;
+  nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
+  RefPtr<gfxFont> mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
+  if (mathFont) {
+    defaultRuleThickness = mathFont->MathTable()->Constant(
+        gfxMathTable::FractionRuleThickness, oneDevPixel);
+  } else {
+    GetRuleThickness(aDrawTarget, fm, defaultRuleThickness);
+  }
+  GetAxisHeight(aDrawTarget, fm, axisHeight);
+
+  bool outermostEmbellished = false;
+  if (mEmbellishData.coreFrame) {
+    nsEmbellishData parentData;
+    GetEmbellishDataFrom(GetParent(), parentData);
+    outermostEmbellished = parentData.coreFrame != mEmbellishData.coreFrame;
+  }
+
+  // see if the linethickness attribute is there
+  nsAutoString value;
+  mContent->AsElement()->GetAttr(nsGkAtoms::linethickness_, value);
+  mLineThickness =
+      CalcLineThickness(presContext, mComputedStyle, value, onePixel,
+                        defaultRuleThickness, fontSizeInflation);
+
+  bool displayStyle = StyleFont()->mMathStyle == StyleMathStyle::Normal;
+
+  mLineRect.height = mLineThickness;
+
+  // by default, leave at least one-pixel padding at either end, and add
+  // lspace & rspace that may come from <mo> if we are an outermost
+  // embellished container (we fetch values from the core since they may use
+  // units that depend on style data, and style changes could have occurred
+  // in the core since our last visit there)
+  nscoord leftSpace = onePixel;
+  nscoord rightSpace = onePixel;
+  if (outermostEmbellished) {
+    const bool isRTL = StyleVisibility()->mDirection == StyleDirection::Rtl;
+    nsEmbellishData coreData;
+    GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);
+    leftSpace += isRTL ? coreData.trailingSpace : coreData.leadingSpace;
+    rightSpace += isRTL ? coreData.leadingSpace : coreData.trailingSpace;
+  }
+
+  nscoord actualRuleThickness = mLineThickness;
+
+  //////////////////
+  // Get shifts
+  nscoord numShift = 0;
+  nscoord denShift = 0;
+
+  // Rule 15b, App. G, TeXbook
+  nscoord numShift1, numShift2, numShift3;
+  nscoord denShift1, denShift2;
+
+  GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
+  GetDenominatorShifts(fm, denShift1, denShift2);
+
+  if (0 == actualRuleThickness) {
+    numShift = displayStyle ? numShift1 : numShift3;
+    denShift = displayStyle ? denShift1 : denShift2;
+    if (mathFont) {
+      numShift = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::StackTopDisplayStyleShiftUp
+                       : gfxMathTable::StackTopShiftUp,
+          oneDevPixel);
+      denShift = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::StackBottomDisplayStyleShiftDown
+                       : gfxMathTable::StackBottomShiftDown,
+          oneDevPixel);
+    }
+  } else {
+    numShift = displayStyle ? numShift1 : numShift2;
+    denShift = displayStyle ? denShift1 : denShift2;
+    if (mathFont) {
+      numShift = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::FractionNumeratorDisplayStyleShiftUp
+                       : gfxMathTable::FractionNumeratorShiftUp,
+          oneDevPixel);
+      denShift = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::FractionDenominatorDisplayStyleShiftDown
+                       : gfxMathTable::FractionDenominatorShiftDown,
+          oneDevPixel);
+    }
+  }
+
+  if (0 == actualRuleThickness) {
+    // Rule 15c, App. G, TeXbook
+
+    // min clearance between numerator and denominator
+    nscoord minClearance =
+        displayStyle ? 7 * defaultRuleThickness : 3 * defaultRuleThickness;
+    if (mathFont) {
+      minClearance = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::StackDisplayStyleGapMin
+                       : gfxMathTable::StackGapMin,
+          oneDevPixel);
+    }
+
+    nscoord actualClearance =
+        (numShift - bmNum.descent) - (bmDen.ascent - denShift);
+    // actualClearance should be >= minClearance
+    if (actualClearance < minClearance) {
+      nscoord halfGap = (minClearance - actualClearance) / 2;
+      numShift += halfGap;
+      denShift += halfGap;
+    }
+  } else {
+    // Rule 15d, App. G, TeXbook
+
+    // min clearance between numerator or denominator and middle of bar
+
+    // TeX has a different interpretation of the thickness.
+    // Try $a \above10pt b$ to see. Here is what TeX does:
+    // minClearance = displayStyle ?
+    //   3 * actualRuleThickness : actualRuleThickness;
+
+    // we slightly depart from TeX here. We use the defaultRuleThickness
+    // instead of the value coming from the linethickness attribute, i.e., we
+    // recover what TeX does if the user hasn't set linethickness. But when
+    // the linethickness is set, we avoid the wide gap problem.
+    nscoord minClearanceNum = displayStyle ? 3 * defaultRuleThickness
+                                           : defaultRuleThickness + onePixel;
+    nscoord minClearanceDen = minClearanceNum;
+    if (mathFont) {
+      minClearanceNum = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::FractionNumDisplayStyleGapMin
+                       : gfxMathTable::FractionNumeratorGapMin,
+          oneDevPixel);
+      minClearanceDen = mathFont->MathTable()->Constant(
+          displayStyle ? gfxMathTable::FractionDenomDisplayStyleGapMin
+                       : gfxMathTable::FractionDenominatorGapMin,
+          oneDevPixel);
+    }
+
+    // adjust numShift to maintain minClearanceNum if needed
+    nscoord actualClearanceNum =
+        (numShift - bmNum.descent) - (axisHeight + actualRuleThickness / 2);
+    if (actualClearanceNum < minClearanceNum) {
+      numShift += (minClearanceNum - actualClearanceNum);
+    }
+    // adjust denShift to maintain minClearanceDen if needed
+    nscoord actualClearanceDen =
+        (axisHeight - actualRuleThickness / 2) - (bmDen.ascent - denShift);
+    if (actualClearanceDen < minClearanceDen) {
+      denShift += (minClearanceDen - actualClearanceDen);
+    }
+  }
+
+  //////////////////
+  // Place Children
+
+  // XXX Need revisiting the width. TeX uses the exact width
+  // e.g. in $$\huge\frac{\displaystyle\int}{i}$$
+  nscoord width = std::max(bmNum.width, bmDen.width);
+  nscoord dxNum = leftSpace + (width - sizeNum.Width()) / 2;
+  nscoord dxDen = leftSpace + (width - sizeDen.Width()) / 2;
+  width += leftSpace + rightSpace;
+
+  mBoundingMetrics.rightBearing =
+      std::max(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing);
+  if (mBoundingMetrics.rightBearing < width - rightSpace)
+    mBoundingMetrics.rightBearing = width - rightSpace;
+  mBoundingMetrics.leftBearing =
+      std::min(dxNum + bmNum.leftBearing, dxDen + bmDen.leftBearing);
+  if (mBoundingMetrics.leftBearing > leftSpace)
+    mBoundingMetrics.leftBearing = leftSpace;
+  mBoundingMetrics.ascent = bmNum.ascent + numShift;
+  mBoundingMetrics.descent = bmDen.descent + denShift;
+  mBoundingMetrics.width = width;
+
+  aDesiredSize.SetBlockStartAscent(sizeNum.BlockStartAscent() + numShift);
+  aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + sizeDen.Height() -
+                          sizeDen.BlockStartAscent() + denShift;
+  aDesiredSize.Width() = mBoundingMetrics.width;
+  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
+
+  mReference.x = 0;
+  mReference.y = aDesiredSize.BlockStartAscent();
+
+  if (aPlaceOrigin) {
+    nscoord dy;
+    // place numerator
+    dy = 0;
+    FinishReflowChild(frameNum, presContext, sizeNum, nullptr, dxNum, dy,
+                      ReflowChildFlags::Default);
+    // place denominator
+    dy = aDesiredSize.Height() - sizeDen.Height();
+    FinishReflowChild(frameDen, presContext, sizeDen, nullptr, dxDen, dy,
+                      ReflowChildFlags::Default);
+    // place the fraction bar - dy is top of bar
+    dy = aDesiredSize.BlockStartAscent() -
+         (axisHeight + actualRuleThickness / 2);
+    mLineRect.SetRect(leftSpace, dy, width - (leftSpace + rightSpace),
+                      actualRuleThickness);
+  }
+
+  return NS_OK;
+}